The present invention relates to dynamoelectric machine testing, and in particular to testing methods for motors used in compressors. The invention provides a test weight for determining whether a counterbalanced motor for use in a compressor assembly, for example, will offset the weight of customer or application components within the assembly in actual use. While the invention is described in particular detail with respect to its use in air compression motor applications, those skilled in the art will recognize the wider applicability of the invention disclosed hereinafter.
A counterbalanced motor is attached to a customer application (such as a compressor assembly and produces the energy required to perform a certain function. When a counterbalanced motor fails to offset the attached component, excessive vibration and vibrational noise occurs within the customer application. A correctly balanced motor minimizes this problem.
Commonly, motors for many applications are manufactured by independent motor manufacturers, and latter attached or inserted in the intended application. For example, counterbalanced motors for use in air compressors are assembled independently from the product for which they are intended. These motors are latter connected to or with customer applications at the application manufacturer location. A motor manufacturer has difficulty determining whether the counterbalanced motor will offset the application components, which are secured to the motor, adequately to minimize vibration and noise without actually building the motor into the application or attaching the application component to the motor. Several attempts have been made to counterbalance an application component properly with a counterbalanced motor. One method is to build the motor and the component together and actually test the balance. If the motor fails to counterbalance the component properly, the unit is disassembled, modified and then reassembled. Repetition of this process may occur several times until the weight of the counterbalanced motor reaches the critical amount required to sufficiently offset the application component. This method of testing balance by actual assembly of an application component unit is costly and time consuming. In the alternative, the motor is tested for electrical performance, without test of the counterbalance requirement. While the test procedure is relatively low cost, the operation of the final product maybe unacceptable.